Upper-ocean turbulence during a westerly wind burst: A comparison of large-eddy simulation results and microstructure measurements

The response of the upper ocean to westerly wind forcing in the western equ atorial Pacific was modeled by means of large-eddy simulation for the purpo se of comparison with concurrent microstructure observations. The model was initialized using currents and hydrography measured during the Coupled Oce an-Atmosphere Response Experiment (COARE) and forced using measurements of surface fluxes over a 24-h period. Comparison of turbulence statistics from the model with those estimated from concurrent measurements reveals good a greement within the mixed layer. The shortcomings of the model appear in th e stratified fluid below the mixed layer, where the vertical length scales of turbulent eddies are limited by stratification and are not adequately re solved by the model. Model predictions of vertical heat and salt fluxes in the entrainment zone at the base of the mixed layer are very similar to est imates based on microstructure data.